The goals of the research are to determine the mechanism, subcellular location, and function of the breakdown of phosphatidylinositol and of the formation and continuous turnover of phosphatidic acid which occur in cell membranes in response to neurotransmitters and hormones. Responses to acetylcholine will be studied in two highly specialized tissues - the exocrine pancreas and the avian salt gland. Information from these two tissues will be used to investigate this phenomenon in brain tissue.